Bill Shorten has run a campaign against the 'cruel' budget, arguing it was unfair and based on broken promises. Photograph: Alan Porritt/AAP

Bill Shorten has opened up a 10-point lead over Tony Abbott as preferred prime minister and the Labor opposition is leading the Coalition government by the same margin on a two-party preferred basis, according to the latest Newspoll.

The poll, published in the Australian newspaper on Tuesday, provides a snapshot of the political landscape as the new Senate takes effect and the government contemplates the need to secure the support of six of eight crossbench senators to pass any contentious legislation.

Seven weeks after the government delivered its first budget, the poll shows Shorten holds a 44% to 34% lead over Abbott as preferred prime minister. Shorten’s score was up four points compared with the previous Newspoll a fortnight earlier while Abbott’s was down three points.

The telephone poll of 1,161 voters, which has a margin of error of up to 3%, showed the Coalition would attract 35% of the primary vote if an election were held now, compared with 37% for Labor, 13% for the Greens, and 15% for others.

Based on preference flows at the last election these figures translate to a two-party preferred result of 55% for Labor and 45% for the Coalition.

This represents a two-point increase for Labor since the previous fortnight’s poll. The Coalition won the last election when it attracted 53.5% of the two-party vote and Labor mustered just 46.5%.

Asked whether they were satisfied with the way Abbott was doing his job as prime minister, 31% said they were satisfied and 62% were dissatisfied, translating to a net approval rating of -31. The Australian said this net approval rating was the worst for a prime minister since Julia Gillard scored -34 points shortly before she was rolled by Kevin Rudd last year.

Satisfaction with Shorten’s performance stood at 34% and dissatisfaction declined four points to 41% since the last poll, equating to a net approval rating of -7. Shorten has run a campaign against the “cruel” budget, arguing it was “unfair” and based on broken promises.

The leader of the government in the Senate, Eric Abetz, said he believed voters would ultimately accept the budget changes as necessary.

Abetz told the ABC: “I think you are right that people never like to hear a message of belt tightening, but when it is explained to them I believe the common sense of the Australian people and their sense of decency that it is simply economically irresponsible and morally wrong to steal the inheritance of the next generation and leave them with a legacy of debt so we can maintain our lifestyle today – that is something most Australians would not accept as a fair cop.”

He said the government would seek to get as much of its agenda through the Senate as possible “but where the cards fall, that remains to be determined”.

The Coalition needs to secure support from six of the eight crossbench senators to ensure the passage of any legislation opposed by Labor and the Greens.

“I wouldn’t describe them as a motley crew; they’re all God’s children as far as I’m concerned. We will be working with them on the issues case by case,” Abetz said.

“We will be living with these independent senators for six years, all things being equal, therefore it makes very good sense to adopt the prime minister’s approach, which is not to hector or lecture them but to treat them with the respect that they deserve – treat each case on its merit and each senator as an individual or should they wish to be in a party grouping, then that party grouping.”

Clive Palmer, whose Palmer United party holds three crossbench Senate seats and has a loose voting alliance with a fourth, has indicated he will not be easily swayed by government briefings on proposed legislation.

“First of all we don’t have advisers, we have employees that follow our direction and our party policy, we don’t need to be advised on what to think or what’s the difference between right and wrong,” Palmer told Guardian Australia. “I just have my brain which is very effective and I’m quite happy with my own advice.”